Lewis Bowen - L2 invariants and Benjamini-Schramm convergence

October 30, 2015 - Princeton University
Does there exist a sequence of free subgroups Fk of the isometry group of hyperbolic n-space such that the Cheeger constant of the quotient space Hn/Fk tends to zero as k tends to infinity? I will explain how to answer this (and related questions) when n is even using a curious result of G.